ALSA' snd_pcm_poll_descriptors_count() can fail with -EPIPE after an underrun (e.g. after a pause), so we can't call it directly like this. It's also a bit sloppy to always call audio_nfds(), so instead save the (initial) value returned and pass it to the various functions. Issue reported and fix tested by phoebos (ben [at] bvnf [dot] space), thank you!

With this the alsa backend reports the progresses too, forgot previously.

amused implements pausing as not sending audio at all until resuming, i.e. by doing an underrun. ALSA is more strict than sndio, by default at least, and so we need to call snd_pcm_recover() before we can play again.

used @openbsd.org initially by mistake and got copied around in most files. Since this has nothing to do officially with the OpenBSD project, use my own email address.

Cm on|off renders the pipe in bold too, use Cm on Ns | Ns Cm off to disambiguate.